In the context, I'd say that two orthogonal features are completely independent from each other (i.e. good engineering is independent from success and the other

In the context, I'd say that two orthogonal features are completely independent from each other (i.e. good engineering is independent from success and the other way around). But tangential features do affect each other (i.e. you cannot succeed without good engineering). His point was that a better engineering will give you a slight better chance to succeed (tangential), but that it's so small that's almost imperceptible and can seem to not affect (orthogonal).